1. Field of the Invention
The present invention relates to light-emitting diodes such as LEDs for general lighting, flashing LEDs for cellular phones, and LEDs for key illumination.
2. Description of Related Art
With the reduction in size of electronic devices, light-emitting diodes (hereinbelow referred to as LEDs) used in such electronic devices and the like are required to be further reduced in size and thickness. Surface mount-type LEDs are often used to satisfy the requirements for such LEDs and are generally composed of: an insulating substrate having electrode patterns formed on the surface thereof; a light-emitting element mounted on the substrate; and a light-transmitting sealing resin body that seals the light-emitting element. In the case that such an LED is mounted on the rear side of a motherboard, the LED is placed on the rear side of the motherboard. Then, edges of the upper surface of the substrate are secured to the rear side of the motherboard with the sealing resin body inserted in a hole penetrating the motherboard, and thus, the LED is mounted on the motherboard (see, for example, FIG. 4 and the description on page 4 of Japanese Patent Application Laid-Open No. 2001-326390).
A detailed description of the above LED will be given with reference to FIG. 5. The LED 20 includes: an insulating substrate 21 having a substantially rectangular parallelepiped shape; a pair of electrode patterns 22 and 23 formed on the upper surface of the substrate 21; a light-emitting element 24 mounted on one of the electrode patterns (electrode pattern 23) and electrically connected to the other electrode pattern 22 through a metal wire 25; and a light-transmitting sealing resin body 26 that covers and seals the light-emitting element 24 and the metal wire 25. Moreover, an external electrode 27 is formed in each of the four corners of the substrate 21.
Meanwhile, a motherboard 28 on which the LED 20 is to be mounted has a hole 29 which is provided in and penetrates the motherboard 28, the sealing resin body 26 of the LED 20 is disposed to be inserted in the hole, and the motherboard 28 also has electrode pads 30 on the rear side thereof the electrode pads 30 being formed around the hole 29. The LED 20 is placed on the rear side of the motherboard 28, and the external electrodes 27 are bonded to the electrode pads 30 with solder 31, and thereby the LED 20 is mounted on the motherboard 28.
However, with the conventional technology described above, when the thickness of the substrate 21 of the LED 20 is reduced, the substrate 21 is likely to be fractured or deformed due to the load applied when the LED 20 is mounted on the motherboard 28. Moreover, separation of the sealing resin body 26 from the substrate 21 is likely to occur, for example, due to the bending deformation of the substrate 21.